Telephone receiver



, May 15, 1928. 1,670,193

J. W. DUNGEY 'ET AL v I TELEPHONE RECEIVER Filed April 5, 1927 unnmmm lllllll ahvemtoz w 35% /Ww7 I Patented May 15, 1928. I II unrrsn STATES JOHN WILLIAM DUNGEY Ann ALFRED "teams-r ERNEST nnown, F nonnon, ENGLAND.

TELEPHONE nnonlvna.

I Application filed April 5, 1927, Serial no. 181,137, and in Great Britainlpril a, lead This invention relates to instruments such as telephone receivers, Wireless loud.

speakers and the like in which an electromagnet acts on a vibratory metallic diaphragm (thearmature) and in which provision is desired [for adjustingthe air gap between the diaphragm and the p'ole pieces of the complete 'clectromagnet assemblage for the purpose of adjusting or altering the sensitivity of. the instrument. I Y I In such instruments the complete electromagnetioassemblage acting, on the diaphragm comprises one or more solenoid windings onfla core or cores (hereinafter referred to asthe solenoid unit), and a permanent magnet or magnets, (hereinafter referred to as the magnet unit).

The invention comprises an improved method and meansfor varying theairgap, in construction ture.- v I 1 :In constructions hitherto proposed the solenoid unit is rigidly connected to the permanent magnetrunit and the combined assemblage is given a perpendicular movement directly towards and away from thediaand economy of manufac- ,phragm, as by'means of a screw, or by a movable Wedge, or other means for-obtain- -ing a fineadjustment. I I

In aconstruction according to the'present Y inventions-the solenoid is adjusted in an oblique direction relatively to. the plane of. v the diaphragm;

The permanent magnet unit need not be;

and preferably is not secured to'thesolenoid -nnit,-but may be permanently mounted on the casing, andv in snchcase provision is [made to :maintain the-core or cores-of the 40 magnet unit during themovementof the solenoid unit. 4 r :For example the upper surface OftWO vpermanent horse shoe magnets which are fixedto the bottom of the instrument casing -may be inclined to the planeof thediaphrag-m'and resilient pressure means procvided to fmaintain the core pole pieces in contact with the magnetic surface during adjustments;

is necessary. I a

v The arrangement according to the invention" is particularly applicable for casings or shells'constructed in accordance With Pat- -"ent No; 242,737, according to which the shell orcasing itself-is of magnetic material and ,which permitsa considerable simplification solenoid unit incontact with the permanent A very small movement only I 1,670,193.- sricn,

takes the place: 'the usual permanentmagnet unit, itbeing only necessary to form a slight incline or flat on the base, on which the core pole pieces are shiftably mounted.

Any suitable means maybe provided for moving the solenoid unit, for example a screw-or lever, or rack and pinion. Where the permanent magnet unit is fixed to the casing or constltuted bythe casing (as in Patent No. 242,737), the ends of the core or cores areshaped so thatthe upper surface'remains parallelto the diaphragm plane. I I I I a.

In order furthermore particularly to describe and ascertain the invention, particu lar constructions in accordance"therewith 1 Figure 2 shows a transverse sectional view of the apparatus shown in Fig. 1.

' Figure 3 is sectionalfview of'ainodi fied form of the invention.

Figured is a plan view of the 'ap rnu's *shown in Fig. 3.

form or embodiment of the invention.

represented by the same reference 1etter.-

In the construction illustrated byFigures Figure 5 is 'a sectional view-ofa third' l and 2 the casing A'is constructed in ac cordance with Patent No.3 242,737, the base B thereof having localized afreasfof mag.

netization 'The base B itself constitutes the permanent. 'inagnet unit. "The phragm C is'c-lamped between the upper pe' ripheryof the casingA' and a supporting frame 'I) as byscreivs G; jThe-framework D is provided withthree supporting legs-E,

(onlytWo of- Which appear in iil16' 'fi 1116),. and may have the usual tubular opening F In the base B a slot H is cut- 'along the slope; Two pole pieces I, Which. are "L shaped in cross section, are mounted to slide on the pole faces along the inside of the base 13.

portions of the pole pieces I, and has shaped flange K fto which apertures through which the upstanding limbs of the pole pieces pass.

K has also-a central depending strip "K passing through the slot-H, and through )slotted arched spring-plate glib-This spring-plate L7 is held in contact with the under surface ofthe base B byshort pins M through the depending portion K of the "edbloclz Q on the casing A, so that, by rotatingthe screw, the solenoid unit is adjustable along the slope, andthe upper ends of the pole pieces I are consequently adjusted towards and away from the diaphragm. v I

It will thus be seen that If, for example,

the adjusting rod 'P has threads per" inch, and the slope of the base B isl in iO relatively to thehdiaphragm that a substantial adjustment of' of an inch is possible with awcomplete rotation oft-he of adjustmentdesired. v

In the modified construction illustrated'in FiguresB ands the casing A is of non the base B, as by means of two non-mag' netic .cross strips :8 and screws 5 symmetrically with respect to the slot Hin the base. The base 1 of each pole piece I is sufficiently wide and long to span the oppo- {site ends of the magnets R, B on which the bases l slide;

The polepieces I may be resiliently held down as before by a similar non-magnetic plate K; spring plate L, pins M, and similarly adjusted by a screw rod 1 obviously possible.

justment oi the solenoid unit'might be ef fected by alever mechanism, or a rack noid winding and pole pieees-forming w sole- 3 In 'a further constructional modification p -fiat base for the casing, sald base beingf'inillustrated by [Figure 5, the pole pieces I may be rigidly mounted together with the r permanent horse shoe magnets R on the non-magnetic plate K, the latter being directly mounted on the slotted sloping base 7 l3 asin the previous constructiens, and similarly adjusted by the screw P.

-Various constructional For example the admechanism in lieuof the screwed rod P.

Instead of a. slopingbase B the upper The plate fan shape, 'slightly deeper one side than the rod P The above dimensionsmay "obviously be altered according to the fineness modifications are surface of the casing on which the diaphragm rests may slope; ora wedge shaped ring may be fitted onthe top of an ordinary casing; or the diaphragm may be pressed other. v p

The means i'orresi-liently holding the sole noidunit on its base support may be varied. H

' The invention would also beequally applicable for an instrument in which a single pole solenoid unit isemployed.

We claim: y 1.A telephone receiver comprising a casing, a diaphragm supported on said casing, a flat base for said casing, said base being inso clined relatively to the diaphragm, a s'ole noid unit supported on said' incl'ined "base, and means for adjusting the positionofth'e solenoid unit on said base.

.2. A telephone-receiver comprising a easing, a diaphragm supported on said casing, a flat base for said casing, said-base being" imclined relatively to the diaphragm, a solenoid unit supported on-said inclined base,

- noid unit on said base, and means for guiding the said solenoid unitduring' the adjustment.

I 3'. A telephone receiver c'omprisingaces ing, a diaphragmsupported on said casing, a

flat base for the casing, said base having a diametrieal slot and being inclined relatively to the diaphragm, a solenoid unitsupportd on said inclined base, an ektensionplate ear-r ried on said solenoid time and projecting "through the slot in the'base, and means for adjusting the position of the solenoid unit "upon the base. 7

4. A telephone receiver comprising 8, casing, a diaphragm supportedon' said casing, 21 fiat base'for the casing, said base having a: diametrical slot and being inclined relatively to the diaphragm, a solenoidu-nit supported on said-inclined base, an extension of nonmagnetizable material projecting from the said solenoid unit through the slot in said incline'dfbase, a spring plate secured to the said non-mag'net-izable extension and maintained in contact with the underside of'sa-id base, and means for adjusting the position of the solenoid unit on said base.

5. A telephone receiver comprising a casing, a diaphragm'supported'on said casing, a

6. A'telepho'ne receiver comprisinga 'casa ing, a diaphragm supported on'said casing, a fiat base for thecas'ing, said basebeing in- 'olined relatively to the dia hragm, ,sole-=- noid unit, a permanent magnet with its poles 1:0

in contact with thepole pieces ofsaid so1enoid unit, a block in the-casing having internally screw-threaded means, and a screwthreaded rod for adjusting the position of the solenoid unit upon the inclined base, said rod being secured to said solenoid unit and passing through the internally screw-thread:

ed means of said block to the exterior of the.

casing.

7 A telephone receiver comprising a casmg, a diaphragm supported on said caslng, a fiat base for the caslng, said base be1ng'1n clined relatively to the diaphragm, a permanent magnet carried by the inclined base, a solenoid unit supported upon said magnet,

means for maintaining the poles of the magnet and the pole-pieces of the solenoid unit in contact With one another and means for adjusting the position of said solenoid uni upon said inclined base.

8. A telephone receiver comprising a cas ing, adiaphragm supported-on said casing, a flat base for the cas1ng,.sa1d base being in clined relatively to the diaphragm, a permanent magnet carried by the inclined base,'.a solenoid unit supported upon said magnet,

means for maintainingthe' poles of the magnet and the pole pieces of the solenoid unit JOHN WILLIAM DUNGEY.

ALFREDERNEST DROWN. 

